Current connection for electric lamps.



H. R. SARGENT. CURRENT CONNEC'HON FOR ELECTRIC LAMPS.

APPLICATION FILED DEC.26. I914.

Patented Dec. 19, 1916.

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HDWARD R. SARGENT, 01F SCHENEGTADY NEW YORK, ASSIGNOR TO ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

CURRENT GONNEC'IION FUR ELECTRIC LAMPS.

Specification of Letters Iatent.

Patented lice. l9, rare.

Application filed. December 26, 1914:. Serial No. 879,030.

To all whom it may concern:

Be it known that I, Howann It. SAnonn'r, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Current Connections forElectric Lamps, of which the following is a specification.

My invention relates to current connections such as are used forelectric lamps and the like, and it includes both bases or plugs andcorresponding sockets or receptacles that are especially suitable forthe mounting and electrical connection of such lamps, though alsoapplicable and adaptable to other uses.

The invention is more particularly concerned with the transmission ofsuch relatively heavy currents as are required by high candle powertungsten filament incandescent lamps containing nitrogen or other gas orvapor and operating at very high efficiency. it is important that whensuch a lamp is inserted in a socket or receptacle each of theconnections necessary to complete its circuit should. be made with goodcontact over ample area, in order that the parts shall not be liable toinjurious or dangerous overheating, and also for other reasons; How thisand other requirements may be met and various advantages obtainedthrough my invention will appear from the following discussion and fromthe detailed description of particular enibodiments hereinafter, whileits scope will be indicated in my claims.

In accordance with my invention, I secure good contact and currentcarrying capacity by providing the base or plug device with terminalshaving coacting screw threaded contact surfaces and providing the socketor receptacle device with terminals having correspondingscrew threadedcontact surfaces, sothat each of the connections necessary to completethe circuit is a screw thread connection. lhe terminals ofthese'connection devices can e constructed and arranged in a greatvariety. of ways, of which only a few are herein specificallyillustrated or referred to.

In the accompanying drawings, Figure 1 is a sectional view illustratinga very simple lamp base and socket construction em bodying my invention.Fig. 2 is a fragmentary view, partly in section, showing a lamp with adiiierent type of base also can 'screw shell terminals 12 and 13 alsoWhile accurate workmanship and. the or As shown in Fig. 1, the terminalsof the lamp base 1 consist of two electrically separate screwthreadedshells :2 and 3 of diflei ent diameters or sizes, arrangedcoarlally one within the other and mechanically united by a body ofinsulating material 'For the sake of a large cavity for the end ofa highpower lamp, the base 1 is pro vided with an ordinary enlarged andinsulated skirt 5. The current leads 6 and I of thejlamp are soldered tothe terminals 2 and 3 in very much the usual way.

The socket or receptacle 1.1 which receives the base 1 compriseselectrically separate ranged coanially one within the other, the

' former being of such diameter that the large base terminal 2 willscrew into it easily but snugly, and the latter being similarly adapt edto screw into the small base terminal.

The terminals 12 and 13 are secured to an insulating body structure 14by screws l5 and a bolt 16, this bolt 16 and two of the screws 1.5serving as parts of their current connections. terial of the bodystructure 1i forms a casing about the terminals 12 and 13 and also formsa stud 17 for mounting the small ter-- minal 13. Though. the externaland nal screw threaded contact surfaces of cl base terminals 2 and 3which coact in ustablishing electrical connections are oi dii? ferentdiameters, they may be oi subs ...itially the same pitch, and the likeapplies to the corresponding screw threaded con tact surfaces of thesocket terminals 12 and 13:

The socket terminals 12 and 13 are so arranged that-When the base i isinserted in intoconcurrent threaded engagement with both of them, firstengaging the latter a little in advance of the former, howe er.

nar s rin iness oi the metal will. result in As shown, the insulatingniatill contact between the threads of each of the base terminals 2 and3 and those of the corresponding socket terminals 12 and 13, suchcontact can be insured by allowing considerable backlash or play in thethreads and making those of the terminals 2 and 12 of Very slightlydifferent pitch from those of the terminals 3 and 13, so that the base 1can be screwed far enough into the socket 11 before jamming occurs.

Referring, now, to Fig. 2, it will be seen that the base 31 here showndiffers from the base of Fig. 1 in that its coaxial electricallyseparate screw shell terminals 32 and 33 are arranged endwise and thatthe screw threaded contact surfaces of both are external. Preferably thepitch of the screw threads of the large terminal 32 is greater than thatof the threads of the small terminal 3.3, for reasons which will appear7 hereinafter. The terminal 32 may be ofthe same size as the screw shellof the base commercially known as the Mogul, and the terminal 33 of thesize of the screw shell of the ordinary medium base, and the insulatingmaterial 34 may unite them mechanically to one another and to theenlarged skirt 35 in the manner illustrated in U. S. Patent No. 775,689to Swan, granted Nov. 22, 1904. As shown, the terminal shell 33 is notmade'as a closed cap like the terminal 3 of Fig. 1, but with an openlower end from which the insulation 34 projects enough to insure againstthe production of a short circuit if an ignorant person should screw thelamp into an ordinary medium screw socket.

Referring to Fig. 3, it will be seen that the socket or receptacledevice 41 for the base or plug device 31 has screw shell terminals 42and 43 which are arranged one within the other with their coactinginternal differentially screw threaded contact surfaces coaxial and aremovable relatively to one another when engaging the corresponding baseterminals 32 and 33. The terminals 42 and 43 are mounted on a bodystructure 44 of porcelain, bisque, or other insulating material whichforms a casing about them, the large terminal 42 being fixedly securedby screws 45, while the small terminal 43 is spring mounted so as to beresiliently yielding in an axial direction. As shown, the termlnal shell43 is in the form of a cup with an angular hole in its bottom, and it isexternally insulated by cap-like shell 46 of fiber, poreelain,'bisque,or other insulating material. For mounting the movable or loose terminal43 with its insulating covering 46 is employed a stud 47 (see Fig. 4)formed of sheet metal suitably punched, bent, and riveted, etc. The headof this stud 47 lies at the bottom of the terminal 43 and may besoldered or otherwise fastened to it, and its angular an inclosing cupor yoke-like shank 48 extends through angular holes in the parts 43 and46 and through a similar hole at the bottom of a circular recess in thebottom portion of the body structure 44. A heavy helical compressionspring 49 in this recess around the shank 48 urges the terminal 43 withits associated parts outtends, while its inward movement is limited bythe body structure 44 itself.

Referring to Figs. 3, 5, and 6, it will be seen that the insulating bodystructure 44 is. provided with a pair of lugs or feet 51 pierced toreceive screws for securing the socket in position, and also with lugs52 that carry binding posts 53, 54, for the connection of the currentsupply wires. From the binding post 53 electrical connection to theterminal 42 is through two screws 55, a metal piece 56 in. a recessatthe bottom of the body structure 44, and two of the screws 45; from thebinding post 54 it is through two screws 57, a metal piece 58 with whichthey engage, and a flexible laminated lead 59 composed of a number ofthin copper strips soldered to said piece 58 and clamped to the shank 48by the piece 50.

It will be seen that the movable or floating terminal 43 with itsassociated parts is restrained or prevented from turning rela tively tothe terminal 42 and its associated body structure 44 by the engagementof the shank 48 with the said body structure, and that axial movement ordisplacement of said terminal 43 from the position shown (which is itsnormal one) is yieldingly resisted by the spring means '49. When thebase 31 is inserted in the socket 41 and turned clockwise, it comes intoconcurrent threaded engagement with both of the socket terminals 42 and43; but the socket parts are preferably so proportioned and arrangedthat meshing and engagement occur between the terminals 32 and 42 soonerthan between the terminals 33 and 43, because with this action anyfailure of the terminals 33 and 43 to mesh when they first come incontact (owing to defective workmanship or error in assembling theparts) will not cause a jamming, but merely result in the loose orfloating terminal 43 being forced inward rather rapidly by furtherturning of the base until the terminal 33 does mesh and engage with itproperly. Once the terminals 32 and 42 and 33 and 43 are in threadedengagement further turning of the base 31 will force the loose terminal43 slowly inward at a rate depending on how much less its pitch is thanthat ofthe terminal 42, and the resulting progressive compression of thespring 49 will terminals will insure good contact pressure over a goodarea. The spring 49 can, however, be dispensed with or made too weak toproduce such pressure and good result obtained if the base 31 is simplyscrewed into the socket 41 until the fioatingsocket terminal 43 isfirmly jammed or wedged at the inner limit of its movement, the partsbeing, of course, so designed that such jamming will occur before thebase'terminal 33 bottoms in the socket terminal 43. practicable to block.or entirely do away with movement of the socket terminal 43 if thedifi'erence of'pitch between the terminals 32 and 42 on the one hand andthe terminals 33 and 43 on the other is made small and the backlash orplay between base and socket 33 will not mesh and engage with themovable socket terminal 43 when it first encounters it, but. only afterit has forced it inward a certain distance against the resistance of afairly stiff, strong spring 49.

WVhile I have, in accordance-with require-v ments of the patentstatutes, shown and described the best form of embodiment of theinvention known to me, I do not'desire to restrict'myself thereto;moreover, I hereby wish to disclaim inventorship of the rela- It is alsotively movable or floating terminal and the differential threading ofterminals, the same being the inventions respectively of Frederick H.Weston and John A. Orange.

What I claim as new and desire to secure by Letters Patent of theUnited. States is 1. A high current lamp connection comprising a socketor receptacle device having electrically separate terminals withcoacting screw threaded contact surfaces of different diameters and abase or plug device for said socket having terminals with correspondingscrew threaded. contact surfaces.

2. A high current lamp connection device comprising electrically.separate terminals with coacting screw threaded contact surfaces ofdifferent diameters for concurrent threaded engagement with threadedterminals of a corresponding connection device.

3. A high current socket or receptacle comprising electrically separateterminals with coaxial coacting screw threaded contact surfaces ofdifferent diameters for concurrent threaded engagement with threadedterminals of a corresponding base.

4. A high current base comprising electrically separate terminals withcoaxial coacting external screw threaded contact surfaces of differentdiameters for concurrent threaded engagement with terminals of acorresponding socket.

5. A high current base comprising in one unitary structure terminalsfor'the lamp circuit having coacting screw threaded contact surfaces anda body of insulating material serving to unite said terminalsmechanically while separating them electrically said base having acavity for the end of the lamp.

In witness whereof, I have hereunto set my hand this 24th day ofDecember, 1914.

HOWARD R. SARGENT.

'lVitnesses:

BENJAMIN B. HULL, IIELEN Onrono.

